diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index b26257c0a8d..d73bab97c15 100644
--- a/src/backend/utils/adt/pg_locale.c
+++ b/src/backend/utils/adt/pg_locale.c
@@ -953,7 +953,7 @@ get_iso_localename(const char *winlocname)
 	wchar_t		wc_locale_name[LOCALE_NAME_MAX_LENGTH];
 	wchar_t		buffer[LOCALE_NAME_MAX_LENGTH];
 	static char iso_lc_messages[LOCALE_NAME_MAX_LENGTH];
-	char	   *period;
+	const char *period;
 	int			len;
 	int			ret_val;
 
diff --git a/src/port/chklocale.c b/src/port/chklocale.c
index 034939f7fd2..023a7435c9b 100644
--- a/src/port/chklocale.c
+++ b/src/port/chklocale.c
@@ -202,7 +202,7 @@ static char *
 win32_get_codeset(const char *ctype)
 {
 	char	   *r = NULL;
-	char	   *codepage;
+	const char *codepage;
 	uint32		cp;
 	WCHAR		wctype[LOCALE_NAME_MAX_LENGTH];
 
diff --git a/src/port/getopt_long.c b/src/port/getopt_long.c
index f83de0dff97..20953db9db1 100644
--- a/src/port/getopt_long.c
+++ b/src/port/getopt_long.c
@@ -62,7 +62,7 @@ getopt_long(int argc, char *const argv[],
 			const struct option *longopts, int *longindex)
 {
 	static char *place = EMSG;	/* option letter processing */
-	char	   *oli;			/* option letter list index */
+	const char *oli;			/* option letter list index */
 	static int	nonopt_start = -1;
 	static bool force_nonopt = false;
 
diff --git a/src/port/win32setlocale.c b/src/port/win32setlocale.c
index 7c0982439db..71574f42de9 100644
--- a/src/port/win32setlocale.c
+++ b/src/port/win32setlocale.c
@@ -119,7 +119,7 @@ map_locale(const struct locale_map *map, const char *locale)
 		const char *needle_start = map[i].locale_name_start;
 		const char *needle_end = map[i].locale_name_end;
 		const char *replacement = map[i].replacement;
-		char	   *match;
+		const char *match;
 		char	   *match_start = NULL;
 		char	   *match_end = NULL;